PARKERSBURG, Iowa — A high school coach who helped launch several professional football careers was gunned down in front of students yesterday by a former player who was to have been taken to a psychiatric ward days earlier, authorities said.

Mark Becker, 24, who was to have gone to the hospital psychiatric ward after allegedly leading police on a high-speed chase Saturday, unloaded several rounds into Aplington-Parkersburg High School football coach Ed Thomas and was arrested in the driveway of his parents’ home soon afterward, said Kevin Winker, assistant director of the Iowa Division of Criminal Investigation.

Winker said he couldn’t discuss what Becker’s motive might have been or what he might have been doing in the days leading up to the shooting.

“Motive is one of those things we’re looking into,” Winker said.

School was not in session and Becker did not threaten any of the students who were in the weight room at the time participating in an offseason workout, he said. Authorities did not release details about the gun that was used.

Thomas, 58, died at a Waterloo hospital. His shooting stunned the rural community of 1,800 residents 80 miles northeast of Des Moines, and it reverberated through NFL circles, where he was remembered as much for his faith as his winning record.

Named the NFL’s 2005 high school coach of the year, Ed Thomas amassed a 292-84 record and two state titles in 37 seasons as a head coach — 34 of them at Aplington-Parkersburg.